Manufacture of window envelopes



Sept. 18, 1934. P. BECKER ET AL v MANUFACTURE OF WINDOW ENVELOPES FiledMarch 6, 1951 lllllllll LL W Patented Sept. 18, 1934 UNITED STATESPATENT OFFICE 1,974,098 MANUFACTURE or wmnow ENVELOPES Maine ApplicationMarch 6, 1931, Serial No. 520,68

lin Germany March 10, 1930 2 Claims. (CI. 3412) The present inventionrelates to the manufacture of window envelopes of the one piece type,that is, envelopes in which anintegral portion of the face of eachenvelope blank 5 is rendered wholly or substantially transparent bytreatment with a suitable penetrating varnish or similar substance.

Heretofore, in the manufacture of one piece window envelopes, theenvelope blanks after receiving the imprint of varnish, have beensubjected to a period of heating at high temperature for the purpose ofrendering the transparentizing solution thinner and promoting itspenetration into the paper. It has been found, however, that when therelatively high heat is maintained long enough to insure thoroughimpregnation of the window portions by the varnish and completedryingthereof, detrimental effects on the texture of the paper andfading of the color of the same have resulted.

According to the present invention, the above mentioned disadvantagespreviously associated with the manufacture of window envelopes areeliminated by successively passing the treated blanks through a seriesof heated chambers, in each of which the temperature is adapted to beseparately controlled. This improved arrangement permits envelope blanksmade from different grades of paper to be subjected successively todesirable and readily varied heat changes, to obtain completeimpregnation of the envelope material by the varnish and completedrying, without ever subjecting the blanks to the, detrimental effectsof excessively high temperatures. The invention further provides aneasily operated mechanism of large capacity through which envelopeblanks may be passed rapidly, thereby obtaining a high rate ofproduction of completed blanks. v 40 r The above and other advantageousfeatures will more fully appear from the following de-' scription takenin connection with the accompanying drawing, in whieh:-

' Fig. 1 is a view in side elevation of a machine embodying theinvention.

Fig. 2 is a fragmentary view illustrating the mechanism for deliveringfinished blanks, the

parts of Fig. 2 being adapted to cooperate with;

the left hand end of the machine shown in Fig. 1.

Like reference characters refer to like parts in the diiferent figures.

The apparatus of the present invention is arranged to operate on treatedenvelope blanks as successively presented by a suitable window printingand varnishing machine 1 and comprises a heating and drying device 2through which the treated blanks travel on a conveyor system, thecontinuous operation of which finally carries the blanks to deliverymechanism 3, adjacent the varnishing machine 1. The individual blanksare printed and varnished by any suitable mechanism in the machine 1, asfor example, by a mechanism of the type shown in United States PatentNo. 1,540,295 issued to Swift June 2, 1925, in which an ink border isprinted on the outer face of each envelope blank and subsequently theimpregnating and transparentizing fluid is applied to its inner face. Asthe treated blanks emerge from the varnishing machine 1, a belt 4delivers them to a transfer belt 5 which conveys the blanks into theheating and drying device 2, next to be described.

The heating and drying device 2, according to the invention, comprisesan enclosure 6, the major portion of which is divided into a pluralityof separate chambers 7, 8 and 9 by partitions 10 and 11 of heatinsulating material. Each of the chambers '7, 8 and 9 is separatelyheated and the temperature thereof'is adapted to be separatelycontrolled in any convenient manner, as for example, by heating elementsof any suitable typ such as variable resistance electrical heating coils12. The blanks are conveyed through these chambers, successively, by-

acontinuous conveyor system comprising, in

, rollers 16 and 17, which latter may be provided with cogs, not shown,to mesh with links in the chains.

Treated blanks are delivered by the conveyor belt 5 to fingers 15 on theupwardly moving side of the chain 13 of the first chamber 7 and arecarried upwardly thereby into the heated upper portion of the chamber '7and then down- 105 wardly to connecting transfer belts 18 and 19 bywhich the blanks are removed from the chain 13 of chamber '7 anddelivered to the chain 13' of chamber 8. The blanks, are then carriedupwardly in a similar manner into the n heated portion of the secondchamber 8 and then downwardly to transfer belts 20 and 21, which serveto deliver the blanks to the endless .chain 13" of the third chamber 9.After passvails the belt 23 being supported by idler rolls 25, as itconveys the blanks beyond the main enclosure 6, and beneath thevarnishing machine 1 to the delivery mechanism 3, which as shown in Fig.2 serves to pile the blanks in any suitable manner'for removal. Whilethe blanksare being carried on this belt 23, beneath the heatingchambers, the residue from the varnish, or other transparentizing fluid,is further dried by the comparatively low heat, and is allowed to coolenough so that it is solidified before it reaches the delivery mechanism3. Consequently, successively delivered blanks may be stacked withoutsticking together.

The various chambers of the drying device 2 may be heated to any desiredtemperatures to accomplish the desired impregnation and drying. Forexample, in treating blanks of light weight paper, the temperature ofthe chamber 7 through which the blanks are first carried may be about.

45 centigrade, to thin the transparentizing material and permit thepaper to be impregnated without appreciable drying; in the secondchamber 8 a somewhat higher temperature, for example, 60 C., may prevailwhich causes the transparentizing material to become still thin-t nerand thoroughly soak and penetrate the paper; in the last chamber 9 asomewhat higher temperature, for example C., may prevail, in the absenceof moisture, to obtain rapid drying of the material. If desired,ventilating devices may be provided in the various chambers to carrythefumes away and eflfect quicker drying. The temperature variations notedabove are suggestive only of one method of treatment, and obviouslydifierent ranges of temperatures may be employed for different grades ofpapers.

The. invention may be further adapted for intermittent heating andcooling of' the blanks, as any chamber may be maintained at atemperature lower than the adjacent chambers. Be-

cause of the transfer'from one chamber to another in a zone below theseveral heat sources, it will be apparent that the blanks are permittedto cool somewhat while passing between successive chambers and that intravelling on the belt 23, the finished blanks will be thoroughly driedbefore stacking.

It will be apparent that, due to the great length of conveyor system bywhich the blanks are carried up and down through the several dryingchambers, the device will handle at one time a much greater number ofenvelopes than a single chamber drier, and willfurthermore permit theblanks to be passed through the drier at a greater speed than in thesingle chamber. Since the blanks remain at the top of each chamber onlya very brief time, they are not subjected 'to the high temperaturesprevailing there for a long enough time to soften the varnish and causeits spreading on the blanks, outside the window areas.

We claim: H i 1. In apparatus for treating envelope blanks, a heatingand drying device comprising a plurality of vertical chambers, avertically arranged endless conveyor chain in each of said chambers forconveying the blanks upwardly and downwardly in each of said chambers,individually operated transfer mechanisms for conveying the blanks fromone conveyor chain to another at the lower portions of said chambers andadjacent the lower portions of the conveyor chains, and means forcontrolling the temperature in each of the chambers individually.

2. In apparatus for treating envelope blanks, a heating and dryingdevice comprising a plurality of vertical chambers, a verticallyarranged endless conveyor chain in each of said chambers for conveyingthe blanks upwardly and downwardly in each of said chambers, individu-,ally operated transfer mechanisms for conveying the blanks from each ofsaid conveyor chains to the successive conveyor chain in an adjacentchamber, said transfer mechanisms operating to transfer the blanks atpoints adjacent the lower portions of the chambers and adjacent thelower portions of the conveyor chains, and means for controlling thetemperature in each of the chambers individually.

PETER BECKER. FRITZ POPPENBURGER.

